Is Shader Model 6 more demanding than SM5?

Hi,
I’m developing a 5.3 project which is not using either Nanite or Lumen. Technically speaking, I could easily fallback to SM5 as I’m not using any features which require SM6. However, after lecturing this page, I now have second thoughts on whether I should switch to SM5 or not. The multithreading aspect of SM6 sounds like a big deal. In practice, is SM6 more performance friendly than SM5? I expect it to use more shader instructions per material, but then again, is this even a problem at runtime considering UE preloads shaders anyways?

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Copilot says:

Let me explain the differences between Shader Model 5 (SM5) and Shader Model 6 (SM6) in Unreal Engine:

  1. Functionality:
  • SM5: It supports standard shading features like textures, lighting, shadows, and visual effects.
  • SM6: Introduces advanced features such as Nanite (virtualized geometry) and Lumen (real-time global illumination) .
  1. Performance:
  • SM6 offers performance improvements due to its multithreading capability. It can better utilize CPU resources and speed up shader processing.
  • However, SM6 may require more shader instructions per material. While UE precompiles shaders, consider this at runtime .
  1. Hardware Compatibility:
  • SM5 is widely compatible and works on various graphics cards.
  • SM6 requires a DirectX 12 and Shader Model 6-compatible graphics card to leverage all its features .

If you’re working on a project in Unreal Engine 5.3 that doesn’t use Nanite or Lumen, you might consider using SM5 if you don’t need the advanced features of SM6. However, if you seek better performance and have compatible hardware, exploring SM6 could be interesting .

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Lumen works with SM5. Just saying… :wink:

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I confirm it!

But in 5.3 or 5.4, I think Unreal was asking for SM6 like more mandatorily, but I don’t remember fine… Previously it was asking for it only when VSMs enabled.

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